How do I replace Android Icon in Side Drawer menu

I have created a side menu use one of the templates. I would like to replace the icon in the menu item. Can I just drag and drop an Android Icon which is listed on the left panel into the properties panel for the menu item? If so, how do I do it?

I want to use an Android Icon which is listed in the left side "Widgets" panel as an image for a button. I create a button. I go to the newly created buttons "Properties" panel. I scroll down to "Background" section. There is an option to "Add Image". I would like to add one of the Android Icons from the left side as an image for the button. When I click on "Add Image", a file chooser dialog pops up. I don't know where the files are for the Android Icons which are listed on the left side reside. How can I add one of the Android Icons as the image for a button? Or is there an entirely different way to create a button with an Android Icon as the background image?

In more general terms, I do not understand how to use Android Icons. They appear to be images because when I drag and drop then on a screen, they are listed as an image. Can I use these Android Icons as an "image" for a background of a button without having to know where the actual file resides?

I could just create a button with no title or image and then overlay the Android Icon image but it would be nice to have the Android Icon image as the background image of the button, using just an single widget (the button) rather than having two widgets (a button and an image)